PSG1, PSG6, PSG6N, and PSG11 induce dose-dependent secretion of anti-inflammatory cytokines by human monocytes. Human and murine PSGs exhibit cross-species activity. Our results are consistent with a role for PSGs in modulation of the innate immune system.

The interaction of transcription factors with target genes is highly dynamic. Whether the dynamic nature of these interactions is merely an intrinsic property of transcription factors or serves a regulatory role is unknown. Here we have used single-cell fluorescence imaging combined with computational modeling and chromatin immunoprecipitation to analyze transcription complex dynamics in gene regulation during the cell cycle in living cells. We demonstrate a link between the dynamics of RNA polymerase I (RNA Pol I) assembly and transcriptional output. We show that transcriptional upregulation is accompanied by prolonged retention of RNA Pol I components at the promoter, resulting in longer promoter dwell time, and an increase in the steady-state population of assembling polymerase. As a consequence, polymerase assembly efficiency and, ultimately, the rate of entry into processive elongation are elevated. Our results show that regulation of rDNA transcription in vivo occurs via modulation of the efficiency of transcription complex subunit capture and assembly.

These findings demonstrate that 633 nm laser light upregulates CGRP mRNA and support the theory that laser irradiation increases the rate of regeneration, target reinnervation, and neuronal survival of the axotomized neuron.

Summary WNT1 and WNT3a have been described as having redundant roles in promoting the development of neural crest-derived melanocytes (NC-Ms). We used cell lineage restricted retroviral infections to examine the effects of WNT signaling on defined cell types in neural crest cultures. RCAS retroviral infections were targeted to melanoblasts (NC-M precursor cells) derived from transgenic mice that express the virus receptor, TVA, under the control of a melanoblast promoter (DCT). As expected, over 90% of DCT-TVA+ cells expressed early melanoblast markers MITF and KIT. However, by following the fate of infected cells in standard culture conditions, we find that only 5% of descendents were NC-Ms. The majority of the descendents were not NC-Ms, but expressed smooth muscle cell markers, demonstrating that mammalian melanoblasts are not committed to the NC-M lineage. RCAS infection of DCT-TVA+ cells demonstrated that overexpression of canonical WNT signaling genes (betaCAT, WNT3a or WNT1) can increase NC-M numbers in an endothelin dependent manner. However, WNT1 and WNT3a have different modes of action with respect to melanoblast fate. Intrinsic over-expression of betaCAT or WNT3a can increase NC-M numbers by biasing the fate of DCT-TVA+ cells to NC-Ms. In contrast, the DCT-TVA+ melanoblasts cannot respond to WNT1 signaling and do not alter their fate towards NC-M. Instead, WNT1 only increases NC-M numbers through paracrine signaling on melanoblast precursors to increase the numbers of neural crest cells that become NC-Ms.